Delete unnecessary BASE_STATE_DIRECTORY_LOCK in TabPersistentStore

chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java

Index: chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java
index 439d9f12aad227afea41a9a80d291ff2a0276820..fd870da029d87051ff1206444a8f04a97e6bb582 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tabmodel/TabPersistentStore.java
@@ -63,9 +63,6 @@ public class TabPersistentStore extends TabPersister {
     /** Prevents two copies of the Migration task from being created. */
     private static final Object MIGRATION_LOCK = new Object();
 
-    /** Prevents race conditions when setting the sBaseStateDirectory. */
-    private static final Object BASE_STATE_DIRECTORY_LOCK = new Object();
-
     /** Prevents two TabPersistentStores from saving the same file simultaneously. */
     private static final Object SAVE_LIST_LOCK = new Object();
 
@@ -205,9 +202,7 @@ public class TabPersistentStore extends TabPersister {
      */
     @VisibleForTesting
     public static void setBaseStateDirectory(File directory) {
-        synchronized (BASE_STATE_DIRECTORY_LOCK) {
-            sBaseStateDirectory = directory;
-        }
+        sBaseStateDirectory = directory;
     }
 
     /**